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2 Sheets-Sheet 1. O. E. SORIBNER. TELEPHONE EXCHANGE SWITCHING APPARATUS. No. 330,065.

Patented Nov. 10, 1885.

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, C. E. SGRIBNER.

TELEPHONE EXCHANGE SWITCHING APPARATUS.

N0. 330,065. Patented NOV. 10, 1885. L 1 E h I J ug Ill L O f: O g/ Fig.2

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UNITED STATES PATENT triers.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE-EXCHANGE SWITCHING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 330,065, dated November 10, 1885. 7

Application tiled February 25, 1884. Serial No. 122,014.

To all whom it may concern.-

Be it known that 1, CHARLES E. SORIBNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented acertain new and useful Improvement in Telephone Exchange SwitchingApparatus, (Case 74,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings forming a part of this specification.

My invention relates to switch-boards for telephone-exchanges, and particularly relates to that class of switch-boards on which the connections are established between any two telephone-lines by means of terminal plugs connected in pairs to flexible conductingcords.

The object of this invention is to provide means for automatically grounding one plug of a pair when the other plug of a pair is taken up in making a connection.

My invention consists in the combinations of the circuits and devices herein described and claimed.

In the drawings, Figurel is a diagram view showing a switch-board provided with circuits and apparatus embodying my invention. Fig. 2 is a diagram view showing in detail the arrangement of a single pair of plugs. Fig. 3 is a detailed view of a'modification of the means employed for carrying out my inven tion.

Referring to the drawings, A represents a switch-board of the ordinary type, provided with any number of switches or terminal bolts, to which the individual telephone-lines are connected.

a of, b b 0 0 represent the plugs connected in pairs with flexible conducting-cords in the usual manner for making a connection between any-two subscribers. In making aconnection between two subscribers with any pair of plugs the operator first takes up that plug of the pair marked a, b, or c. We will therefore call these plugs the first plugs of the respective pairs. The other plugs, a b c", we will call the second plugs. The plugs are all adapted to be drawn up out of the way when not in use. This is preferably accom- (No model.)

plished by passing the conducting-cords of each pair of plugs over a pair of movable pulleys, (1 01 each pair of said movable pulleys being attached to a pair of weights, h h, by a pair of weight-cords, e 6. These weightcords e e are run over a pair of fixed metallic pulleys, f f at the front, and at the rear over a similar pair of pulleys, g 9 The front 7 pulleys, f y, and the rear pulleys, g are insulated from each other by being secured to a frame of wood, or in any other suitable manner.

Ihave shown a loop-key included in the circuit of each pair of plugs, said loop-keys being adapted,when depressed, to include the operators telephone outfit in circuit, and when thrown up to disconnect the telephone outfit and include a clearing-out aununciator in circuit in the manner substantially as set forth in my application No. 112,307 filed November 20, 1883. The loopkeys are shown at 70, Z, andm and the clearing-out annunciat- 01s at a, b, and c, the connections from the conducting-cords to the loop-keys and clearing out annunciator being indicated by dotted lines.

It is desirable that the operators outfit be connected directly in circuit with the subscribers line by the act of inserting a plug into an individual switch, so that the operator may speak directly to the subscribers. It is also desirable that the operators o 1 n l in circuit with the connected subscribers when the connection is completed by inserting the second plug of a pair in the switch of the subscriber called for, so that the operator can make the call and then ascertain whether the connection is properly made. To accomplish this the operators outfit is normally connected to all the plugs-that is, all the loopkeys are normally depressed-and means are provided whereby a ground-connection is established with the second plug of a pair when the first plug of the pair is taken up for use,

metallic serving up to the point t.

purpose being constructed substantially as set forth in my application No. 97,672, filedJune 11, 1883. The plates 19 are connected, respectively, to the front metallic pulleys, f f f, as indicated by lines r r 1*. Thus the front metallic pulley of the first plug of each pair is connected to the. metallic plate with which the second plug of the pair is normally in electrical contact. The rear metallic pulley, g, of each pair is connected directly to ground, asindicated by line 3. The weightcord 6 of each pair is made of a non-conducting material, but is covered for a portion of its length with a metallic serving. This metallic serving is adapted when the first plug is drawn out for use to establish an electrical connection between the front metallic pulleys, f, and the rear metallic pulley, g, and thus ground the second plug through plate p. In Fig. 2 the cord 6 is shown covered with the When the first plug is in its normal position, the point t is at a point in the rear of the front pulley, f, and there is no electrical connection between the front and rear pulleys, f and g, and the line r is open at pulley f. It will be seen that the metallic serving on weight-cord 6 acts as a switch to automatically ground the sec ond plug of a pair when the first plug is taken up for use. It is evident that this switch may be modified in various ways.

In Fig. 3 a spring attached to the platep is adapted to make contact with a ground contact point when the first plug of a pair is taken up for use, said spring being normally held away from said contact-point by the said plug. The same result is accomplished as with the metallic serving. It is obvious that a metallic weight-cord, 6, may be used, said cord being insulated where it rests normally on the front metallic pulley, f.

IVhen the first plug of apair-for instance,

' plug cis drawn down until the metallic serving on the weight-cord 6 comes in contact with the metallic pulley f, a connection is established between the front pulleys, f, and the rear pulley, g. The second plug, 0", of the pair is thus grounded through the plate 1). In Fig. 1,plug e is shown thus drawn down and inserted in switch 5 on the switch-board A. Its circuit may be traced as follows: from switch 5 through the conducting-cord and connection indicated by dotted line to the upper bar of loop-key m, thence through the operators outfit to the lower bar of loop-key m, and thence to plug 0 from plug 0 through plate 19, line r, front pulley, f, metallic serving of cord 6, to rear pulley, g, and thence to ground through line 8, as before described.

By the arrangement above described I am enabled to have each pair of plugs normally connected to the operators outfit, so that when the first plug of a pair is inserted in a switch the operators outfit is brought directly into circuit with the subscribers line connected to said switch by the automatic grounding of the second plug of the pair. The connection be tween two subscribers is completed by drawing down the second plug of a pair and inserting it into the switch of the subscriber desired. When the second plug of thepair is removed from the metallic plate, the groundconnection claim as new and desire to secure by Letters Patent 1. The combination, with a pair of terminal plugs connecting to flexible cords for connecting telephone-lines, of a metallic plate with which one plug of said pair is normally in electrical contact, and switching devices whereby said plate is automatically grounded when the other plug of the pair is taken up for use, substantially as and for the purpose set forth.

2. The combination, with a series of terminal plugs arranged in pairs, each pair of plugs being normally connected through a common operators telephone-outfit, of metallic plates, one plate for each pair of plugs, saidplates being respectively in electrical contact with one plug of each pair, and switching devices whereby the metallic plate of either pair of plugs is grounded when the first plug of said pair is taken up for use, substantially as 3. The combination, with switches or terminal bolts of two or more telephone-lines, of a branch line or loop provided with plugs for temporarily connecting any two telephonelines together, and switching devices whereby one end of said branch or loop is automatically grounded by the act of making a connection between the other end of said loop and a telephone-line, substantially as described.

4.. The combination, with a pair of connecting-cords with terminal plugs and a metallic plate, 19, with which one plug of the pair is normallyin electrical contact, of metallic pulleysf g" and the metallic cord 0, one of said pulleys being connected with said plates and the other being connected to ground, substantially as described.

In witness whereof I hereunto subscribe my name this 9th day of February, A. D. 1884.

CHARLES E. SORIBNER.

Witnesses:

O. 0. SHEPHERD, GEORGE P. BARTON. 

